PHYSICS REGISTRY REVIEW

In a standing patient, what is the approximate measured pressure at the level of the ankle?

Circulatory pressure only (no change with standing)

Why should you avoid increasing the doppler angle above 70 degrees in Doppler ultrasound?

To prevent increased error production

Which doppler angel negatively affects color power doppler?

90 degrees

which of the following occurs when two waves propagating through tissue arrive in the same location at a single point in time?

Interference

which of the following utilizes two rapid, successive pulses, where the second pulse is the mirror image of the first, to cancel out the fundamental frequency and isolate the harmonic signal?

pulse inversion

what is the term used to describe the measurement of the relative loudness of sounds, dynamic range, and gain in ultrasound imaging?

decibel

what is the functionality of the beam former in the ultrasound machine?

to shape and steer the beam during transmission

which mode is primarily associated with cardiac imaging and represents colors vertically and shades of green horizontally to indicate turbulence?

variance mode

A Reynolds number less than 1500 indicates which of the following conditions?

Laminar flow

what step can a sonographer take to enhance contrast resolution in a grayscale ultrasound image?

decrease compression (increase dynamic range)

which of the following is a function of the pulser used to increase the signal to noise ratio?

coded excitation

during ultrasound imaging, which specific condition results in the creation of a reverberation artifact as the ultrasound beam travels within the patient’s body?

two strong parallel reflectors

how does an increase in imaging depth affect the PRF and Nyquist limit in color flow Doppler imaging?

both PRF and Nyquist limit decrease

what is the term used to describe the process when sound beams leave the transducer, Strike a boundary between two media, and travel back to the probe?

reflection

what is the total distance traveled when the go return time to the reflector is 26 µs?

4 cm

in lower extremities, changing intra-abdominal pressure with expiration has what effect on venous flow?

increased venous flow

What is the most commonly encountered artifact in Doppler ultrasound imaging?

Aliasing

Which of the following components reduces the sensitivity and efficiency of the ultrasound system?

backing material

which of the following increases the amplitude of all returning signals regardless of reflector depth?

overall gain

which of the following is synonymous with lateral resolution?

azimuthal resolution

among the following options, all of the following are synonymous with the term “normal incidence” as it applies to ultrasound imaging, EXCEPT?

Oblique

which of the following statements about thermal index (TI) in ultrasound is correct?

Reducing output power will reduce the TI

what is the term used to describe the resolution of two structures at different depths along the path of the sound beam?

axial resolution

What effect does increasing the PRF have on the Nyquist limit in doppler ultrasound?

increases the Nyquist limit

What metric determines the ability of a medical test to accurately identify positive cases?

Sensitivity

Which of the following should be modified to improve lateral resolution?

decreasing beam width

What is the cause of comet tail artifact?

Reverberation

Why is it important to measure intensities?

To reduce biological effects

Which of the following anatomical structures would have the lowest rate of speed?

Lung

What is the relationship between PRF and PRP?

Inversely proportional

An ultrasound pulse leaves the transducer, travels through liver tissue, reflects off an internal structure, and returns to the transducer in 25 microseconds. Using the time of flight equation and assuming soft tissue propagation of 1540 m/s, what is the depth of the reflector from the transducer?

2 cm

How is the attenuation coefficient of ultrasound in soft tissue related to the operating frequency?

It is equal to half of the operating frequency

What effect would a significant increase in the number of RBCs have on the blood flow of it resulted in the thickening of the blood?

viscosity and resistance increase